How cool is this?  So as you walk away from your PC it will “lock” and then as you come back…boom – it is ready to use.  A post on Lifehacker –   This is a hack for Ubuntu systems.

An intrepid user at the Ubuntu Forums has detailed the installation and setup of BlueProximity, a free Linux app that turns a Bluetooth phone into a proximity-based security device for your computer. Yes, that’s exactly how it sounds: Your laptop locks itself down when you step a certain distance away, and opens again once you’re in range. Certainly useful in coffee shop and book store situations, but not a bad idea in a house with curious little fingers around, either. This kind of measure is more utility than security device, and the instructions require serious attention (forgetting to undo one step could hose your system), but it’s a nice privacy feature and seriously cool tweak at the same time.